1. Field of the Invention
The present invention relates to an evaporator for refrigerating a fluid to be refrigerated (for example, water, brine, and the like) by carrying out heat exchange of the fluid to be refrigerated and to a refrigerant, and relates to a refrigerator provided with the evaporator.
2. Description of Related Art
In a large structure such as a building, for example, water refrigerated by a refrigerator is circulated through piping arranged in the structure and heat exchange with air is carried out in individual spaces in order to perform cooling.
An embodiment of an evaporator provided in a refrigerator is shown in FIG. 9. The refrigerator is composed by providing plural heat-transfer pipes 2 for flowing cold water to a cylindrical container 1 into which a refrigerant is introduced, which are provided zigzaged in a bundle. The heat-transfer pipes 2 are divided into two kind of pipe groups which are outward heat-transfer pipes connecting to an inlet 3 for cold water and backward heat-transfer pipes connecting to an outlet 4 for cold water. Cold water flows in from the inlet 3 for cold water, flows through the outward heat-transfer pipes 2 into a water chamber (not shown in FIG. 9), returns to the water chamber, flows through the backward heat-transfer pipes 2, and flows out from the outlet 4 for cold water. In this step, cold water is refrigerated by heat-exchanging with the refrigerant introduced in the container 1 and as a result, the refrigerant boils and vaporizes.
Since plural heat-transfer pipes are used in a bundle in the conventional evaporator, the boiling refrigerant forms bubbles around the heat-transfer pipes provided at the lower part in the container and the bubbles are around the heat-transfer pipes provided over the lower heat-transfer pipes until the bubbles reach to the surface of the refrigerant. As a result, the rest of the refrigerant, which is not boiling, cannot be sufficiently supplied around the heat-transfer pipes provided at the upper part in the container. In particular, there is a problem in that the heat-transfer pipes provided around the center of the bundle have lower thermal conductivity than that of the heat-transfer pipes provided around them.
In light of the above problem, an aim of the present invention is to provide an evaporator having high thermal conductivity, yielding an improvement in which remaining the bubbles formed by boiling the refrigerant in the container quickly surface without being around the heat-transfer pipes for a long time, and further, to provide a refrigerator having high cooling efficiency, provided with the evaporator.
To achieve the above aim, an evaporator and a refrigerator having the following structure are adopted. That is, the present invention provides an evaporator for refrigerating a fluid to be refrigerated and vaporizing a refrigerant by carrying out heat exchange between the fluid and the refrigerant, comprising plural heat-transfer pipes, in which the fluid flows, provided in a container into which the refrigerant is introduced, wherein the heat-transfer pipes are divided into plural pipe groups and the pipe groups are provided with an interval between adjacent pipe groups.
In this evaporator, since the heat-transfer pipes are divided into plural pipe groups and the pipe groups are provided with intervals between adjacent pipe groups, bubbles generated around the heat-transfer pipes positioned at lower positions of the pipe groups come to the surface through the intervals between adjacent pipe groups, and as a result, the bubbles around the heat-transfer pipes decrease to prevent fall of the heat transfer coefficient.
Furthermore, since the pipe groups are provided with intervals between adjacent pipe groups when the liquid refrigerant introduced in the container flows, the refrigerant flows easily. As a result, contact of the liquid refrigerant and the heat-transfer pipes is promoted to improve the heat transfer coefficient.
Furthermore, in the above evaporator, the plural pipe groups may be provided in a zigzag pattern in the container.
In the evaporator in which the liquid refrigerant is introduced into the lower part of the container and the refrigerant vaporized is flowed out from the upper part of the container, the liquid refrigerant tends to flow upward in the container. Then, the pipe groups are horizontally arranged in a zigzag pattern in the evaporator, and as a result, contact of the liquid refrigerant and the heat-transfer pipes is promoted to improve the heat transfer coefficient.
Furthermore, in the above evaporator, the pipe groups may comprise space in which the heat-transfer pipes are removed.
In the evaporator, since the space is provided in the pipe groups, bubbles rear the center of the pipe groups easily come to the surface. Therefore, bubbles which degrade the performance of the heat-transfer pipes positioned around the center of the pipe groups prevent a fall in the heat transfer coefficient.
Furthermore, in the evaporator, the heat-transfer pipes in all the pipe groups may be provided in a zigzag pattern.
As described above, the liquid refrigerant flows in the container after introduction. In the evaporator, since the heat-transfer pipes are arranged in a zigzag pattern, the refrigerant easily flows in the pipe groups and contact of the liquid refrigerant and the heat-transfer pipes is promoted to improve the heat transfer coefficient.
Furthermore, in the above evaporator, the pipe groups may be horizontally divided and the heat-transfer pipes provided in the pipe groups on the upper level are not more densely (more loosely) arranged than the heat-transfer pipes provided in the pipe groups on the lower level.
In the evaporator, since the heat-transfer pipes provided in the pipe groups on the upper level are not more densely arranged than the heat-transfer pipes provided in the pipe groups on the lower level, when bubbles generated around the heat-transfer pipes of the pipe groups positioned at the lower part of the container, pass through the pipe groups positioned at the upper part of the container, bubbles easily come to the surface through the intervals between adjacent heat-transfer pipes of the pipe groups.
The present invention provides to a refrigerator comprising: an evaporator for refrigerating a fluid to be refrigerated and vaporizing a refrigerant by carrying out heat exchange between the fluid and the refrigerant, comprising plural heat-transfer pipes in which the fluid flows provided in a container into which the refrigerant is introduced, a compressor for compressing the refrigerant vaporized in the evaporator, a condenser for condensing and liquefying the refrigerant compressed, and an expansion valve for decompressing the refrigerant liquefied at a step for flowing the refrigerant liquefied in the evaporator.
In the refrigerator, the heat transfer coefficient of the heat-transfer pipes in the evaporator is improved, and as a result, heat exchange coefficient is improved. Therefore, if energy consumption is set to a low level, performances at the same level as that of a conventional refrigerator, particularly, with respect to the refrigeration coefficient, is obtained.